White Rot Fungus Phanerochaete Chrysosporium Research Articles

English

Chromium as a toxic heavy metal is of major concern due to the various health effects on human and as a pollutant to environ- ment. Chromium makes land desolate by forming toxic soluble chromium compounds in soil and water bodies. At present various microor- ganisms are used for bioremediation of chromium from soil and water bodies. The aim of present work was to bioremediate chromium from synthetic solutions by a white rot fungus Phanerochaete chrysosporium (MTCC787) using in form of viable cells, microbial biosorbent (dried cells) and immobilised cells at different physical parameters i.e. pH, temperature and medium with substrates like Citric acid, Tween 80 and EDTA.

Assessment of the Whole Environmental Degradation of Oxo-Biodegradable Linear Low Density Polyethylene (LLDPE) Films Designed for Mulching Applications

The current paper is aimed at understanding the environmental fate of linear low density polyethylenes (LLDPE) films designed for mulching purposes and loaded with different pro-degradant additives. These were analyzed, upon exposure to natural sunlight for a period intended to mimick a general crop season in the mediterranean region. The selected samples underwent a relatively low extent of degradation as monitored by carbonyl index, molecular weight variation, extractability by solvent, changes in the onset of the decomposition temperature and crystallinity. The tendency to biodegradation of outdoor exposed LLDPE was then assessed under different environmental compartments including soil medium, aqueous medium as well as in axenic culture of white-rot fungus Phanerochaete chrysosporium. That fungus is known to be effective in the degradation of recalcitrant organic materials and plastic items. During the soil burial biodegradation test, lasted for 27 months, samples specimen were withdrawn at time intervals and characterized by means of structural and thermal analysis. These analytical assessments allowed to monitor any progress of oxidative degradation as a direct effect of the incubation in an active microbial environment. Analogous characterizations were carried out at the end of the biodegradation tests in aqueous medium and in P. chrysosporium axenic cultures. Data presented here are in keeping with the initial abiotic oxidation via a free radical chain reaction promoted by a pro-degradant additive acting on hydroperoxides and peroxide moieties present initially in the polymer bulk. This step was followed by a free radical cascade reactions leading to degradation once the oxidation started under relatively mild conditions (sunlight exposure). During the incubation step in soil, the abiotically degraded samples underwent significant variation in the level of oxidation and degradation with respect to the detected starting values. Indications were gained on the synergistic effect of a random fashion microbial metabolization coupled to biotically mediated oxidation of the original abiotically fragmented samples. Similar results were obtained in the biodegradation tests carried out in the aqueous media and in presence of P. chrysosporium axenic cultures. These evidences are suggesting the role of natural occurring microorganisms in promoting both partial oxiditation and degradation of LLDPE samples in combination with contextual mineralization process of the oxidized fragments.

Cloning, expression and characterization of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium strain BKM-F-1767

BackgroundThe white-rot fungus Phanerochaete chrysosporium is among the small group of fungi that can degrade lignin to carbon dioxide while leaving the crystalline cellulose untouched. The efficient lignin oxidation system of this fungus requires cyclic redox reactions involving the reduction of aryl-aldehydes to the corresponding alcohols by aryl-alcohol dehydrogenase. However, the biochemical properties of this enzyme have not been extensively studied. These are of most interest for the design of metabolic engineering/synthetic biology strategies in the field of biotechnological applications of this enzyme.ResultsWe report here the cloning of an aryl-alcohol dehydrogenase cDNA from the white-rot fungus Phanerochaete chrysosporium, its expression in Escherichia coli and the biochemical characterization of the encoded GST and His6 tagged protein. The purified recombinant enzyme showed optimal activity at 37°C and at pH 6.4 for the reduction of aryl- and linear aldehydes with NADPH as coenzyme. NADH could also be the electron donor, while having a higher Km (220 μM) compared to that of NADPH (39 μM). The purified recombinant enzyme was found to be active in the reduction of more than 20 different aryl- and linear aldehydes showing highest specificity for mono- and dimethoxylated Benzaldehyde at positions 3, 4, 3,4 and 3,5. The enzyme was also capable of oxidizing aryl-alcohols with NADP + at 30°C and an optimum pH of 10.3 but with 15 to 100-fold lower catalytic efficiency than for the reduction reaction.ConclusionsIn this work, we have characterized the biochemical properties of an aryl-alcohol dehydrogenase from the white-rot fungus Phanerochaete chrysosporium. We show that this enzyme functions in the reductive sense under physiological conditions and that it displays relatively large substrate specificity with highest activity towards the natural compound Veratraldehyde.

Responses of Phanerochaete chrysosporium to Toxic Pollutants: Physiological Flux, Oxidative Stress, and Detoxification

The white-rot fungus Phanerochaete chrysosporium has been widely used for the treatment of waste streams containing heavy metals and toxic organic pollutants. The development of fungal-based treatment technologies requires detailed knowledge of the relationship between bulk water quality and the physiological responses of fungi. A noninvasive microtest technique was used to quantify real-time changes in proton, oxygen, and cadmium ion fluxes following the exposure of P. chrysosporium to environmental toxic (2,4-dichlorophenol and cadmium). Significant changes in H(+) and O(2) flux occurred after exposure to 10 mg/L 2,4-dichlorophenol and 0.1 mM cadmium. Cd(2+) flux decreased with time. Reactive oxygen species formation and antioxidant levels increased after cadmium treatment. Superoxide dismutase activity correlated well with malondialdehyde levels (r(2) = 0.964) at low cadmium concentrations. However, this correlation diminished and malondialdehyde levels significantly increased at the highest cadmium concentration tested. Real-time microscale signatures of H(+), O(2), and Cd(2+) fluxes coupled with oxidative stress analysis can improve our understanding of the physiological responses of P. chrysosporium to toxic pollutants and provide useful information for the development of fungal-based technologies to improve the treatment of wastes cocontaminated with heavy metals and organic pollutants.

Characterization of PIR1, a GATA family transcription factor involved in iron responses in the white-rot fungus Phanerochaete chrysosporium

Iron, although toxic in excess, is an essential element for biological systems. Therefore, its homeostasis is of critical importance and tight mechanisms participate in its acquisition by microbial organisms. Lately, the relevance of this metal for biomass conversion by wood-degrading fungi has been gaining increasing attention. Iron plays a critical role as cofactor of key enzymes such as lignin and manganese peroxidases in lignin-degrading white-rot fungi, while Fe(II) also serves a pivotal role in Fenton reactions that are central in cellulose depolymerization by brown-rotters. It has been hypothesized that multicopper oxidases with ferroxidase activity might participate in controlling the bioavailability of iron in the hyphal proximity, fine-tuning Fenton chemistry and balancing lignin versus cellulose degradation. In order to further explore the dynamics of iron regulation in the well known white-rot fungus Phanerochaete chrysosporium, we analyzed the mRNA levels of the multicopper oxidases genes (mcos) in response to iron supplementation, confirming down-regulation of their expression in response to this metal. To gain a better understanding on the transcriptional mechanisms mediating this effect, we searched for a gene encoding a GATA-type transcription factor with homology to URBS1, the major transcriptional regulator of iron homeostasis in Ustilago maydis. Due to the limitation of experimental tools in P. chrysosporium, the alleged Phanerochaete iron regulator (PIR1) was studied by complementation of a Neurospora SRE/URBS1-deficient strain, where phenotypic and molecular characteristics of this transcriptional regulator could be easily assessed. In addition, using a genome-wide in silico strategy, we searched for putative cis-acting iron-responsive elements in P. chrysosporium. Some of the identified genes showed reduced transcript levels after 30min in the presence of the metal, consistent with an SRE/URBS1-mediated mechanism, and suggesting a broad effect of iron on the regulation of several cellular processes.

Screening of fungi capable of highly selective degradation of lignin in rice straw

In order to screen for novel fungus with powerful delignification capability on rice straw, fungal samples found on woody surfaces were collected from several regions in China and were isolated and screened for their lignin-degrading properties on rice straw. After the individual isolates were cultivated on rice straw as the sole carbon substrate for 10 days, gravimetric fiber extraction analysis was used to determine the change in holocellulose and lignin content. Isolate 812 exhibited a high degree of lignin degradation at 34.7% while maintaining low holocellulose degradation at 2.1%, which performed better than the traditional white-rot fungus Phanerochaete chrysosporium with 28.3% lignin degradation and 28.4% holocellulose degradation. Isolate 812 was identified as Fusarium moniliforme based on its 18S rDNA gene sequence and its morphological characteristics. Ligninolytic enzyme assay indicated that the fungus produced lignin peroxidase and manganese peroxidase during solid-state and liquid fermentation. Above results indicated that we had screened a F. moniliforme isolate with highly efficient delignification capability and very slight damage to holocellulose. The newly isolated fungus could be used in biodegradation of lignocellulosic feedstock.

Modeling the Biomass Growth and Enzyme Secretion by the White Rot Fungus Phanerochaete chrysosporium: a Stochastic-Based Approach

The white rot fungus Phanerochaete chrysosporium has been identified to be an environmentally useful microorganism for the degradation of various hazardous pollutants, mainly because of its ligninolytic enzyme system, particularly the lignin peroxidase (LiP) secreted by the fungus. In the present work, the behavior of the fungus in liquid medium due to variation in physico-chemical parameters, i.e., glucose concentration, nitrogen concentration, agitation, etc., was studied. Increment of the initial concentration of glucose in the medium increases the biomass growth and LiP activity, when cultured under controlled conditions. The biomass growth and LiP activity by the fungus was modeled following stochastic approach. The behavior of growth and enzyme activity of the fungus observed from the model were found to be in agreement with the experiments qualitatively.

Biological pretreatment of corn stover by solid state fermentation of Phanerochaete chrysosporium

Biological pretreatment is a promising way to overcome the biorecalcitrance of cleaving the supermolecular structure of lignocellulose by lignin degrading enzymes from microorganisms. Solid state fermentation of corn stover with the white-rot fungus Phanerochaete chrysosporium was carried out and the efficiency of this pretreatment was evaluated. The enzymatic hydrolysis yield reached a maximum when the corn stover was biologically pretreated for nine days, and the hydrolysis yield decreased sharply if the solid state fermentation was carried out for more than nine days. A possible explanation for this sharp decrease is that not only the lignin degrading enzymes (LiP and MnP) were secreted, but also other metabolites, which were toxic or fatal to the hydrolysis enzymes resulting in the lower hydrolysis yield were generated during the prolonged period of biopretreatment. These results are useful to help determine the optimal timing and to understand the lignin structure and degradation mechanism in biological pretreatment processes.

Oil-in-water microemulsions enhance the biodegradation of DDT by Phanerochaete chrysosporium

A novel approach was developed using oil-in-water (O/W) microemulsions formed with non-ionic surfactant, cosurfactant (1-pentanol) and linseed oil, at the cosurfactant to surfactant ratio (C/S ratio, w/w) of 1:3 and oil to surfactant ratio (O/S ratio, w/w) of 1:10, to enhance the biodegradation of DDT by the white rot fungus Phanerochaete chrysosporium. Results showed that microemulsions formed with Tween 80 effectively enhanced the biodegradation of DDT by P. chrysosporium and the enhancement was about two times that of Tween 80 solution, while microemulsion formed with Triton X-100 exhibited negative effect. Further studies revealed that microemulsion formed with Tween 80 enhanced the biodegradation of DDT through transporting DDT from crystalline phase to mycelium as well as their positive effect on the growth of P. chrysosporium; of these, the former is likely the most important and pre-requisite for the biodegradation of DDT by P. chrysosporium.

Continuous treatment of coloured industry wastewater using immobilized Phanerochaete chrysosporium in a rotating biological contactor reactor

Coloured industry wastewaters often contain dyes and other toxic ingredients, and, therefore, pose serious threat to the receiving environment. Among the available methods the eco-friendly biological method has gained maximum attention due to its many advantages over the traditional methods. In the present study, continuous biological treatment of coloured wastewater from a textile dyeing industry was investigated using the white rot fungus Phanerochaete chrysosporium in a rotating biological contactor (RBC) reactor. The raw wastewater was diluted with an equal volume of either distilled water or media containing glucose at varying concentrations to study its effect on the decolourization process. Results revealed that the wastewater could be decolourized to an extent of more than 64% when diluted with media containing glucose; and, a maximum decolourization efficiency of 83% was obtained with 10g/l glucose concentration. COD removal efficiencies were also found to be consistent with the decolourization efficiencies of the wastewaters. Further, the results were correlated with the enzyme activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) by the fungus, which were found to play some significant role in decolourization of the wastewater. Results of replacing the costly carbon source glucose in the decolourization media with the more cheap molasses, however, revealed very high COD removal efficiency, but low decolourization efficiency of the industry wastewater.

Elimination of carbamazepine in a non-sterile fungal bioreactor

A properly configured bioreactor is in need to transfer the fungal biodegradation of recalcitrant pollutants into real applications. In this study, a novel plate bioreactor was designed to eliminate carbamazepine (CBZ), a widely concerned pharmaceutical, with the white rot fungus Phanerochaete chrysosporium grown on polyether foam under non-sterile conditions. The bioreactor was operated in both sequence batch and continuous modes. It was found that the sufficient supply with nutrients is crucial for an effective elimination of CBZ. Given the conditions, a high elimination of CBZ (60–80%) was achieved. The effective elimination was stable in a continuous operation for a long term (around 100days). The high elimination of CBZ could also be achieved under real conditions with the effluent from a municipal wastewater treatment plant.

Modelling the Biomass Growth and Enzyme Secretion by the White Rot Fungus <i>Phanerochaete Chrysosporium</i> in Presence of A Toxic Pollutant

The white rot fungus Phanerochaete chrysosporium is well known for its ability to degrade toxic pollutants owing to its efficient extracellular ligninase system. However, biomass growth and enzyme secretion in presence of toxic pollutant is not well understood. In the present study, using the model azo dye Direct Red-80, biomass growth and lignin peroxidase secretion by the fungus was studied during its degradation and a stochastic based model was applied to simulate the behavior of the fungus. Also, glucose concentration in the medium was varied in order to observe its effect on the dye degradation. Results revealed that glucose at an optimum concentration of 10 gL-1 is essential for biomass growth, LiP secretion, as well as the dye decolourization. Modeling the behavior of the fungus with the presence of both glucose and dye has shown significant similarity.

A Fungal P450 (CYP5136A3) Capable of Oxidizing Polycyclic Aromatic Hydrocarbons and Endocrine Disrupting Alkylphenols: Role of Trp129 and Leu324

The model white rot fungus Phanerochaete chrysosporium, which is known for its versatile pollutant-biodegradation ability, possesses an extraordinarily large repertoire of P450 monooxygenases in its genome. However, the majority of these P450s have hitherto unknown function. Our initial studies using a genome-wide gene induction strategy revealed multiple P450s responsive to individual classes of xenobiotics. Here we report functional characterization of a cytochrome P450 monooxygenase, CYP5136A3 that showed common responsiveness and catalytic versatility towards endocrine-disrupting alkylphenols (APs) and mutagenic/carcinogenic polycyclic aromatic hydrocarbons (PAHs). Using recombinant CYP5136A3, we demonstrated its oxidation activity towards APs with varying alkyl side-chain length (C3-C9), in addition to PAHs (3–4 ring size). AP oxidation involves hydroxylation at the terminal carbon of the alkyl side-chain (ω-oxidation). Structure-activity analysis based on a 3D model indicated a potential role of Trp129 and Leu324 in the oxidation mechanism of CYP5136A3. Replacing Trp129 with Leu (W129L) and Phe (W129F) significantly diminished oxidation of both PAHs and APs. The W129L mutation caused greater reduction in phenanthrene oxidation (80%) as compared to W129F which caused greater reduction in pyrene oxidation (88%). Almost complete loss of oxidation of C3-C8 APs (83–90%) was observed for the W129L mutation as compared to W129F (28–41%). However, the two mutations showed a comparable loss (60–67%) in C9-AP oxidation. Replacement of Leu324 with Gly (L324G) caused 42% and 54% decrease in oxidation activity towards phenanthrene and pyrene, respectively. This mutation also caused loss of activity towards C3-C8 APs (20–58%), and complete loss of activity toward nonylphenol (C9-AP). Collectively, the results suggest that Trp129 and Leu324 are critical in substrate recognition and/or regio-selective oxidation of PAHs and APs. To our knowledge, this is the first report on an AP-oxidizing P450 from fungi and on structure-activity relationship of a eukaryotic P450 for fused-ring PAHs (phenanthrene and pyrene) and AP substrates.

Decolourization potential of white-rot fungus Phanerochaete chrysosporium on synthetic dye bath effluent containing Amido black 10B

Synthetic azo dyes are extensively used in textile industry and are not easily degraded into the environment due to their complex structure. Due to the low degree of fixation of these dyes to fabrics, more than 10–15% of the dye does not bind to fabrics during colour processing and release into water bodies as effluent cause serious environmental pollution. White-rot fungus is found to be capable of degrading lignin which has a complex structure similar to azo dyes. In this study, the decolourization potential of white-rot fungus Phanerochaete chrysosporium, which is capable of decolourizing synthetic dye bath effluent, was investigated. Maximum decolourization of 98% was achieved on the third day under normal conditions. The rate of decolourization carried out at different concentrations revealed that the increase in dye effluent concentration suppresses the percentage decolourization. The optimized amounts of nutrients were found to be 0.5%, 0.1% and 0.5% of glucose, manganese sulphate and ammonium salts, respectively. The addition of inducers such as starch and lignin increased enzyme production and the rate of decolourization.

Comparative study of natural and synthetic phenolic compounds as efficient laccase mediators for the transformation of cationic dye

Laccase mediator systems are important bioremediation agents as the rate of reactions could be enhanced in the presence of the mediators. In the present study commercial laccase was used for the biotransformation of malachite green (MG), a cationic dye in the presence of phenolic compounds of groundnut shells and lignin-related synthetic redox mediators. The addition of ethanolic phenolic extract of groundnut shell enhanced the decolorization of MG from 38.73 to 87.32%. All the selected natural phenolic compounds enhanced the decolorization of MG like synthetic mediator 1-hydroxybenzotriazole. Characterization of MG transformation products by UV–vis and HPLC analyses revealed that N-demethylation was the key mechanism of decolorization of MG by laccase alone as well as in the presence some of redox mediators. But in case of MG decolorization with laccase mediated system by groundnut shell extract and other natural compounds, leuco-malachite green was the major transformed product. Growth inhibition test based on mycelial growth inhibition of white rot fungus Phanerochaete chrysosporium (ATCC 1556) revealed that treatment with laccase plus natural and synthetic mediators effectively reduced the growth inhibitory levels of MG than that of control. Thus, the study revealed that the natural phenolic compounds could be used as potential redox mediators for enhanced laccase-mediated decolorization of malachite-green dye.

Characterization of proteome alterations in Phanerochaete chrysosporium in response to lead exposure

BackgroundTotal soluble proteome alterations of white rot fungus Phanerochaete chrysosporium in response to different doses (25, 50 and 100 μM) of Pb (II) were characterized by 2DE in combination with MALDI-TOF-MS.ResultsDose-dependent molecular response to Pb (II) involved a total of 14 up-regulated and 21 down-regulated proteins. The induction of an isoform of glyceraldehyde 3-phosphate dehydrogenase, alcohol dehydrogenase class V, mRNA splicing factor, ATP-dependent RNA helicase, thioredoxin reductase and actin required a Pb (II) dose of at least 50 μM. Analysis of the proteome dynamics of mid-exponential phase cells of P. chrysosporium subjected to 50 μM lead at exposure time intervals of 1, 2, 4 and 8 h, identified a total of 23 proteins in increased and 67 proteins in decreased amount. Overall, the newly induced/strongly up-regulated proteins involved in (i) amelioration of lipid peroxidation products, (ii) defense against oxidative damage and redox metabolism, (iii) transcription, recombination and DNA repair (iv) a yet unknown function represented by a putative protein.ConclusionThe present study implicated the particular role of the elements of DNA repair, post-tanscriptional regulation and heterotrimeric G protein signaling in response to Pb (II) stress as shown for the first time for a basidiomycete.

Cytochrome b5 reductase–cytochrome b5 as an active P450 redox enzyme system in Phanerochaete chrysosporium: Atypical properties and in vivo evidence of electron transfer capability to CYP63A2

Two central redox enzyme systems exist to reduce eukaryotic P450 enzymes, the P450 oxidoreductase (POR) and the cyt b5 reductase–cyt b5. In fungi, limited information is available for the cyt b5 reductase–cyt b5 system. Here we characterized the kinetic mechanism of (cyt b5r)–cyt b5 redox system from the model white-rot fungus Phanerochaete chrysosporium (Pc) and made a quantitative comparison to the POR system. We determined that Pc-cyt b5r followed a “ping-pong” mechanism and could directly reduce cytochrome c. However, unlike other cyt b5 reductases, Pc-cyt b5r lacked the typical ferricyanide reduction activity, a standard for cyt b5 reductases. Through co-expression in yeast, we demonstrated that the Pc-cyt b5r–cyt b5 complex is capable of transferring electrons to Pc-P450 CYP63A2 for its benzo(a)pyrene monooxygenation activity and that the efficiency was comparable to POR. In fact, both redox systems supported oxidation of an estimated one-third of the added benzo(a)pyrene amount. To our knowledge, this is the first report to indicate that the cyt b5r–cyt b5 complex of fungi is capable of transferring electrons to a P450 monooxygenase. Furthermore, this is the first eukaryotic quantitative comparison of the two P450 redox enzyme systems (POR and cyt b5r–cyt b5) in terms of supporting a P450 monooxygenase activity.

Glutathione Transferases of Phanerochaete chrysosporium: S-GLUTATHIONYL-p-HYDROQUINONE REDUCTASE BELONGS TO A NEW STRUCTURAL CLASS

The white rot fungus Phanerochaete chrysosporium, a saprophytic basidiomycete, possesses a large number of cytosolic glutathione transferases, eight of them showing similarity to the Omega class. PcGSTO1 (subclass I, the bacterial homologs of which were recently proposed, based on their enzymatic function, to constitute a new class of glutathione transferase named S-glutathionyl-(chloro)hydroquinone reductases) and PcGSTO3 (subclass II related to mammalian homologs) have been investigated in this study. Biochemical investigations demonstrate that both enzymes are able to catalyze deglutathionylation reactions thanks to the presence of a catalytic cysteinyl residue. This reaction leads to the formation of a disulfide bridge between the conserved cysteine and the removed glutathione from their substrate. The substrate specificity of each isoform differs. In particular PcGSTO1, in contrast to PcGSTO3, was found to catalyze deglutathionylation of S-glutathionyl-p-hydroquinone substrates. The three-dimensional structure of PcGSTO1 presented here confirms the hypothesis that it belongs not only to a new biological class but also to a new structural class that we propose to name GST xi. Indeed, it shows specific features, the most striking ones being a new dimerization mode and a catalytic site that is buried due to the presence of long loops and that contains the catalytic cysteine.

Bioremediation of Chromium from Fortified Solutions by Phanerochaete Chrysosporium (MTCC 787)

Pollution by chromium is of major concern as the metal is used in electroplating, metal finishing leather tanning and chromate preparation. Chromium found in water bodies and in soil is in the form of Cr (III) and Cr (VI). Cr (VI) being of particular concern because of its greater toxicity. At present various microorganisms are used for bioremediation of heavy metals from soil and water bodies. The aim of present work was to bioremediate chromium from fortified solution by a white rot fungus Phanerochaete chrysosporium (MTCC787). The potency of Phanerochaete chrysosporium was evaluated to remediate chromium from fortified solution by viable cells, microbial biosorbents and immobilized cells for the first time. The percentage removal of chromium was analyzed by UV-Visible spectrophotometer (HitachiU-2900). The study shows 99.7% Cr (VI) was removed by biosorption with Phanerochaete chrysosporium detected spectrophotometrically after 72 hrs. This study shows that Phanerochaete chrysosporium is highly potential to be used for the removal of chromium which is also a viable, eco friendly and cost effective technology for cleanup of chromium (VI).

Mycelial growth and solid-state fermentation of lignocellulosic waste by white-rot fungus Phanerochaete chrysosporium under lead stress

Lignocellulosic biomass is an abundant renewable resource difficult to degrade. Its bioconversion plays important roles in carbon cycles in nature, which may be influenced by heavy metals in environment. Mycelial growth and the degradation of lignocellulosic waste by lignin-degrading fungus Phanerochaete chrysosporium under lead stress were studied. It was shown that P. chrysosporium could grow in liquid media with 400 mg L −1 Pb(II), and mycelial dry weight was reduced by 54% compared to the control. Yellow mycelia in irregular short-strip shape formed in Pb-containing media, whereas the control showed ivory-white regular mycelial pellets. Two possible responses to Pb stress were: dense hyphae, and secretion from mycelia to resist Pb. During solid-state fermentation of straw, fungal colonization capability under Pb stress was positively correlated with the removal efficiency of soluble–exchangeable Pb when its content was higher than 8.2 mg kg −1 dry mass. Carboxymethyl cellulase activity and cellulose degradation were inhibited at different Pb concentrations, whereas low Pb concentrations increased xylanase and ligninolytic enzyme activities and the hemicellulose and lignin degradation. Cluster analyses indicated that Pb had similar effects on the different microbial indexes related to lignin and hemicellulose degradation. The present findings will advance the understandings of lignocellulose degradation by fungi under Pb pollution, which could provide useful references for developing metal-polluted waste biotreatment technology.